The general object of our biomedical image processing program is to apply modern techniques for automatic image processing to the performance of appropriate and necessary biomedical observations. The goal of the research project proposed herein is to develop an automatic cytogenetic analysis system for radiation health monitoring purposes in order to make feasible the use of readily generated quantitative information concerning chromosome aberrations in populations potentially or actually exposed to ionizing radiation. Such populations include workers in the nuclear industry, members of the public inadvertently exposed to accidentally released radioactivity, people whose living environment is demonstrated to contain a higher level of natural or man- made radioactivity than the usual and individuals undergoing diagnostic or therapeutic x-ray or radioisotope exposure for medical reasons. The project involves the development of an automatic microscope to scan cytogenetic slide preparations, locate dividing cells and collect the information by flying spot scanner in a computer-compatible form, systems engineering to control the microscope with a PDP-7 computer and to transfer the information to a PDP-10 computer system, and software development for storage, manipulation, and analysis of cytogenetic data, as well as its correlation with environmental exposure and health data of the populations under study. A reference set of manually analyzed cells from 1000 randomly selected newborns and 51 sequentially- studied radiation over-exposure patients is available for validation studies. Our specific aims are to complete automatic mitotic cell locator performance tests; to improve the optics and flying spot scanner of the automatic microscope; and to develop and test software for automatic detection of aberrant chromosomes in irradiated human metaphase cells.